Fuse link



Oct. 28, 1947. J. YONKERS 2,429,906

FUSE LINK Filed Sept. 11, 1944 Patented Oct. 28, 1947 UNITED STATES PATENT OFFICE FUSE LINK 19.11;; L, Xonkers, Evanston, 111., assignor to .Jcslyn Man fa t ring and pply o p y, Qhicag 1111-, a orpo ation of Illinois Application September 11, 1944, SerialNo. 553,514

.5 Claims. 11

The present invention relates to ruse links and m re particularly to improvements in hi h oltas: use links adapted ior use in ope type outou s.

links adapted-for usein co ventional typ of .open cut-outs are usually prouided with at least one flexible plgt-ail conductor, the end of which is attachable to a spring arm of cutout vassembly to place the conductor and at least certain fusible parts of the link under tension. In order to facilitate attachment of the pighail -..c.0nd.uctor to the cut-cut spring arm, it is com.- .mon -practice to provide .a tool receiving ,or conduster manipulating loop at the end of the pig tail conductor. Typi al loop arrangements .ieh s pu pose a e shown by .Fox Patent No. 2.200, .496, Lemmon Pat No. 2,2 8, and Fox Patent No. 2,304,250. In all such structures, special parts are req red in the r a ion of he loops, and the loops are of a permanen cha a ter n tha t ey cannot be removed or isassembled without destroying .a segment of the pigtai-l conductor. As :a result, fuse links employing such loop structures are somewhat costly to manufac tune and are not susceptible of un form u e op n typ cut-cuts @of the character mention d and in those typ s of cut-puts in which the pig tail conductor is simply clamped .to a :tensioning element.

.I is an ob ect of the p e nt invention em fore t p vide a fus ink havin aristai-l con .d-uctor equipped with an exceedingly simple tool receiving loop at the end thereof.

According at! another object .of .the invention the Pigtail loop structure is .of such arrangement I that it may be easily and rapidly normed at the end of the pigtail c nductor and may b just as easily removed from the end .of the .condu tor to prod ce a corr spondin elon ation of the on ductor.

In accordance with still another object of the invention the loop arrangement is such that :a simple washer of appropriate size maybe em- 1 ed both to lock the meeting ends .of the 1001 against disengagement .and to act as a shoulder stop against which the .tensioning element .of a cut-out assemblymay bear.

The invention, both as to its organization and method .of production, to ether with further ebiects and advantages thereof, will bestfpe under: stood by reference to th iollowing specification, taken in connection the accompanying drawings, in which;

Fig. .1 illustrat s a fuse of improved constructicn having a projectin meted conductor in which the present improved loop structure may beformed;

Fig. 2 illustrates certain deformation steps involved in the production of the loop structure;

Fig. 3 illustrates the completed p structure and the manner in which the pigtail conductor .rnay be tensioned between the terminal elements of ,a cut-out assembly; and

Fig. 4 illustrates the configuration of one of the terminal elements shown in Fig. 3.

Referring now to the drawing, the fuse link there illustrated comprises a metallic tubular housing 410 within which the working parts of the link are housed, and upper metallic contact lbutton [0a and a lower contact sleeve lllb which is insulated from the metal parts 10 and la and is electrically and mechanically connected to a pig-tall conductor l I. Preferably the component parts of the fuse link and more particularly the working parts enclosed by the tubular housing 1:8 are of the improved construction and arrange ment disclosed and claimed in copending application Serial No. 533,824, filed May 3, 1944, Edward 'I-I. Yonkers, and assigned to the same assignee as the present invention. In brief, these parts of the link include at least one fusible element disposed within the housing I0 and electrically and mechanically .connected to the contact sleeve 10b and the upper end of the conductor .l I, .so that when the pigtail conductor is placed under tension by applying a tensioning force between the contact button Illa and a lower part of the conductor, the contact sleeve I fib and any unfused portion of the fusible element will be withdrawn from the tubular housing 10 :to produce arc elongation upon rupture of the fusible element.

Referring now more particularly to the present improved pigtail loop structure and the meth- 0d of forming the same, it is pointed out that the pigtall conductor H is in the form of a flexible tube. More specifically, this conductor is comprised of a tubular arrangement of braided wires. Before the loop is formed at the end of the conductor a standard washer l3 having an inner diameter substantially equalling that of the conductor is strung on the conductor and moved tnerealong to a point above that portion .of the conductor from which the loop is to be formed. As best shown in Fig. 2 of the drawing, inorder to form the tool receiving loop at the end of this conductor, the sharp point of an awl-like tool 14 having a uniform diameter slightly greater than the diameter of the conductor H is inserted between the wires of the conductor at one side thereof and at an appropriate intermediate point I 5 along the length of the conductor. After the initial insertion is made, the end of the tool is telescoped through the conductor away from the contact sleeve [db to expand the conductor along a segment IS of the length thereof. Incident to this operation, the wires at the point of tool insertion are spread apart to form an opening 20 having a diameter equalling the diameter of the tool I4. Following the described operations, the tool I4 may be withdrawn from the conductor II without closing the opening 20 or disturbing the expanded condition of the conductor segment I5. To complete the loop, the lower end portion of the conductor II is sharply bent at a point I? therealong to provide a straight portion I8 adapted for insertion into the expanded segment I5 of the conductor. After this bend is made the conductor end 49 is inserted through the opening 26 and the end segment I8 of the conductor is telescoped within the expanded segment In this regard it is noted that the length of the end segment I3 is slightly less than the length of the expanded segment I6, thus providing for seating of the bent conductor portion I! upon the lower edge of the opening 29.

It has been found that a loop constructed in the manner just described is not readily susceptible of disassembly by tool forces of the character normally applied along the lower portion of the loop in attaching the pigtail conductor to the spring arm of a cut-out assembly. To emphasize this point, one method of supporting the fuse link is illustrated in Fig. 3 of the drawing. As there shown, the link is held between a stationary terminal element 2! and a spring arm 23 of an open cut-out assembly. More specifically, the upper end of the tubular housing I is inserted between the upturned tines 22 of the rigidly mounted forked end terminal element 2| so that engagement of the button head contact lfla with the tines 22 provides the sole support for the link. In order to tension the fusible element housed within the tubular member II], the pigtail conductor II is detachably connected at the point-i therealong to the end of the spring arm 23. In this regard it will be understood that suitable facilities are provided in the cut-out assembly for biasing the outer end of the arm 23 away from the stationary terminal element 2|. The spring arm may be of the construction shown in Fig. 4 of the drawing. As there illustrated this arm is provided at its extreme outer end with parts 24 and 25 which extend back from the end of the arm to define conductor receiving slots 26 and 2! upon opposite sides of the arm.

In the assembly of the link upon the cut-out structure the tubular housing I0 is first positioned within the tines 22 of the upper terminal member 2| to support the link from this member. Following this operation the hook at the end of a pigtail manipulating tool is inserted through the loop at the lower end of the pigtail conductor to tension this conductor, and a second tool is used to raise the spring arm 23 to a point such that it is disposed above the point I5 along the conductor. The loop holding tool is now manipulated to move a portion of the conductor which is disposed above the point I5 therealong into one of the slots 28 and 2?. Following these operations, the spring arm 23 may be released to thrust against the washer I3 and thus tension the fusible element within the tubular housing I0 and that portion of the pigtail conductor ex- 4. tending between the contact sleeve [0b and the point I5. In this regard it is noted that the lower surface of the washer I3 abuts the end portion of the pigtail conductor II at the bent point I! therealong such that it is positively restrained in a set position at the point I5 along the conductor. Further, the spring pressure exerted upon the upper surface of the washer I3 by the spring arm 23 serves positively to lock the end segment I8 of the conductor against removal from the expanded segment [6 thereof.

As indicated above, if it desired to use the described fuse link in a cut-out which requires a long pigtail conductor but no loop at the lower end of this conductor, the described loop structure may be quickly and easily removed from the conductor. To this end, the conductor end portion I8 is withdrawn from the expanded conductor segment I6 and straightened by finger manipulation. Following this operation a slight jerk may be applied to the conductor at the ends thereof for the purpose of reducing the expanded segment I6 to its original diameter and of closing the opening 25 in the side of the conductor. After the conductor is thus restored substantially to the configuration shown in Fig. 1 of the drawing, the washer I3 may obviously be withdrawn therefrom.

From the above explanation, it will be apparent that the manipulating loop may be quickly and easily formed at the end of the conductor II without the use of specially stamped connecting parts and with but a single tool. It may just as easily be removed from the end of the conductor without using any tools. In this regard it will be understood that when the conductor II is in the form shown in Fig. 1 of the drawing the link may be used on any type of cut-out having screw or wedge type facilities for clamping the end of the conductor to a biased extracting element of the cut-out structure, and that the conductor may be cut to any required length. The described loop structure has an additional important advantage in that it may be easily produced by linemen in the field. Further, by appropriate selection of the point I5 along the conductor II at which the opening 20 is formed, the seat for the washer I3 may be located different distances away from the button head contact Ifla. Thus the link is readily adaptable for use in many different types of cut-out structures having different dimensions between the terminals thereof.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein which are within the true spirit and scope of the invention as defined in the appended claims.

I claim;

1. In a fuse link, a hollow flexible pigtail conductor electrically connected to a fusible element of the link and provided with an opening in one side thereof at an intermediate point therealong, said conductor also having an end portion telescoped within said intermediate portion through said opening to provide a manipulating loop at th end of said conductor.

2. In a fuse link, a pigtail conductor electrically connected to a fusible element of the link and comprising a tubular arrangement of braided wires, the wires at one side of said conductor being spread apart to provid an opening into the conductor at an intermediate point along the length of the conductor and the end portion of said conductor being telescoped within said intermediate portion of said conductor through said opening to provide a manipulating loop at the end of said conductor.

3. In a fuse link, a pigtail conductor electrically connected to a fusible element of the link and extending away from one end of the link, said conductor comprising a tubular arrangement of braided wires, the wires at one side of said conductor being spread apart to provide an opening into the conductor at an intermediate point along the length thereof and the wires extending from said opening away from said one end of the link being expanded over a short segment of the conductor to increase the space defined therebetween, and the end portion of the conductor being telescoped within said short segment of the conductor through said opening to provide a manipulating loop at the end of said conductor.

4. In a fuse link, a hollow flexible pigtail conductor electrically connected to a fusible element of the link and provided with an opening in one side thereof at an intermediate point therealong, said conductor also having an end portion telescoped Within an intermediate portion thereof through said opening to provide a manipulating loop at the end of said conductor, and a washer strung on said conductor above said loop and adapted to be tensioned against the end portion of the conductor at the point of entry into said opening, thereby to restrain said washer against movement along said conductor beyond said point and to lock the end portion of said conductor within said intermediate portion of said conductor.

5. In a fuse link, a pigtail conductor electrically connected to a fusible element of the link and extending away from one end of the link, said conductor comprising a tubular arrangement of braided wires, the wires at one side of said conductor being spread apart to provide an opening into the conductor at an intermediate point along the length thereof and the wires extending from said opening away from said one end of the link being expanded over a short segment of the conductor to increase the space defined therebetween, and the end portion of the conductor being telescoped within said short segment of the conductor through said opening to provide a manipulating loop at the end of said conductor,

and a washer strung on said conductor above said loop and adapted to be tensioned against the end portion of the conductor at the point of entry into said opening, thereby to restrain said washer against movement beyond said point away from said one end of the fuse link and to lock the end portion of said conductor within the expanded segment of said conductor.

JOHN L. YONKERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,751,405 Herman Mar. 18, 1930 2,106,007 Klein Jan. 18, 1938 2,324,044 Triplett et al July 13, 1943 2,208,099 Lemmon July 16, 1940 2,090,609 Lemmon Aug. 17, 1937 2,200,496 Fox May 14, 1940 

